CN103370299B

CN103370299B - For the production of the technique of (methyl) vinylformic acid and derivative and the polymkeric substance produced from it

Info

Publication number: CN103370299B
Application number: CN201280008311.1A
Authority: CN
Inventors: 大卫·威廉·约翰逊; 格雷厄姆·罗纳德·伊斯特汉; 马丁·波利亚科夫; 托马斯·安德鲁·哈德尔
Original assignee: Lucite International UK Ltd
Current assignee: Mitsubishi Chemical UK Ltd
Priority date: 2011-02-09
Filing date: 2012-02-08
Publication date: 2016-06-01
Anticipated expiration: 2032-02-08
Also published as: KR102013910B1; US9216938B2; MX2013009025A; EA201391138A1; UY33901A; SG191982A1; CA2825258A1; EA026117B1; US20140031501A1; JP6046639B2; EP2673253A1; WO2012107758A1; CN103370299A; AU2012215191B2; TWI529157B; MY165885A; EP2673253B1; JP2014513043A; NZ613224A; ES2677363T3

Abstract

Describe a kind of method that (methyl) vinylformic acid is extracted into the organic phase being in contact with it from aqueous reaction medium. Aqueous reaction medium is formed by least one alkaline catalysts in aqueous and at least one dicarboxylic acid that is selected from toxilic acid, fumaric acid, oxysuccinic acid, methylene-succinic acid, citraconic acid, methylfumaric acid and citromalic acid or its mixture and contains the decarboxylate of the base catalysis of base catalyzed reactions. Method comprises at least one in described dicarboxylic acid and/or its presoma being joined in aqueous reaction medium makes alkaline catalysts remain on sub-stoichiometry level than the level of dicarboxylic acid and/or presoma to strengthen in (methyl) vinylformic acid solvent extraction to organic solvent or during extraction process. Method expansion is to the technique producing (methyl) vinylformic acid, its ester and its polymkeric substance and multipolymer.

Description

For the production of the technique of (methyl) vinylformic acid and derivative and the polymkeric substance produced from it

The present invention relates to by the technique producing (methyl) vinylformic acid (meaning acrylic or methacrylic acid herein) or derivative such as its ester from the extraction of reaction medium of the decarboxylation under the existence of alkaline catalysts of selected acid He (methyl) acrylic acid product.

Vinylformic acid (AA) and methacrylic acid (MAA) and their ester, particularly methyl esters, second ester and fourth ester, such as ethyl propenoate, butyl acrylate, methyl methacrylate (MMA) and butyl methacrylate are the important monomers in chemical industry. Their main application is in the production of the polymkeric substance for various application. The most important polymer application be vinylformic acid in super absorbent polymer, and methacrylic ester and acrylate are used for Surface coating and for by the high optics property the known plastics of the casting of polymethylmethacrylate (PMMA), molding or extrusion. In addition, many multipolymers of AA and its ester and MAA or MMA are used; Important multipolymer is the multipolymer of MMA and AAAAAAAAAAAA vinyl toluene, ethyl propenoate and butyl acrylate. At present, AA, MMA and MAA produce from petrochemical material completely.

Routinely, MMA is industrially produced by so-called acetone-cyanalcohol route. Technique is capital intensive and produces MMA with prussic acid with relative high cost from acetone. Technique is caused by forming acetone cyanohydrin from acetone and prussic acid: the dehydration of this kind of intermediate obtains sulfuric acid Methacrylamide, and then it be hydrolyzed to produce MAA. The sulfuric ester that intermediate cyanalcohol is used sulfuric acid conversion to be Methacrylamide, its methanolysis provides monoammonium sulfate and MMA. But, this kind of method is not only high cost, but both sulfuric acid and prussic acid all require careful to handle to keep safety operation and a large amount of ammonium sulfate as by product of explained hereafter with high cost. This kind of ammonium sulfate to the fertilizer that can use or the equipment of conversion requirement high fund cost that returns to sulfuric acid and very big cost of energy.

Selectively, in other technique, it is known to use iso-butylene or, equivalently, trimethyl carbinol reactant starts, and then trimethyl carbinol reactant is oxidized to methacrylaldehyde and is then oxidized to MAA.

The improving technique providing high receipts rate and selectivity and by product less in addition is two stage process being called as �� technique. Stage I describe in WO96/19434 and relate to two (di-t-butyl phosphinomethyl) the benzene part of 1,2-ethene to methyl propionate with the use in the carbonylation of high receipts rate and optionally palladium chtalyst. The applicant also developed the technique of the catalyzed conversion of the use formaldehyde to MMA for methyl propionate (MEP). One is the cesium-promoted catalyst on carrier such as silicon-dioxide for this suitable catalyzer. This two stage process, although being favourable significantly relative to the technique of available competitiveness, but still depends on mainly ethylene raw from crude oil and Sweet natural gas, although bio-ethanol be also the source as ethene can.

Vinylformic acid is produced by the oxidation of propylene routinely, and propylene derives from oil, gas or coal raw material with arranging him.

Within many years, biomass are provided as the alternative form for fossil oil, as potential selectable energy resource and as the selectable resource for chemical technology raw material. Accordingly, one is significantly any in the technique of the production of the raw material implementing the known use biomass source for AA, MMA or MAA for the solution of the dependency to fossil oil.

In this, it is well known that, synthetic gas (carbon monoxide and hydrogen) can derive from biomass and methyl alcohol can be manufactured by synthetic gas. Some industrial plant based on this from synthetic gas methanol, such as, your BiomethanolChemieHoldings is killed at the LausitzerAnalytikGmbHLaboratoriumf �� rUmweltundBrennstoffeSchwarzePumpe of Germany and the Dai Erfu of Holland. Nouri and Tillman, Evaluatingsynthesisgasbasedbiomasstoplastics (BTP) technologies, (ESA-Report2005:8ISSN1404-8167) teaches and uses the methyl alcohol produced from synthetic gas as the feasibility of production of direct material or the raw material such as formaldehyde for other. Also have the production of the synthetic gas of the much production from biomass about being suitable for chemicals patent with off-patent open.

Also set up well in manufacture factory by the producing ethylene by ethanol dehydration of biomass sources, particularly in Brazil.

The glycerine producing propionic acid and biomass sources from the carbonylation of ethanol is also set up in the patent literature well to the conversion of such as propenal and acrylic molecules.

Therefore ethene, carbon monoxide and methyl alcohol have the manufacture route from biomass set up well. The chemicals of this explained hereafter are used by selling with the specification identical with the material in oil/gas source or the technique that is required by identical purity to use wherein.

In principle, therefore, not there is the obstacle of the operation of the raw material production methyl propionate from biomass sources to so-called �� technique above. In fact, the use of simple raw material such as ethene, carbon monoxide and methyl alcohol becomes desirable candidate.

In this, WO2010/058119 relates to biomass clearly for the purposes for �� technique above entering thing and the catalyzed conversion of the formaldehyde to MMA of methyl propionate (MEP) produced. These MEP and formaldehyde raw material can from biomass sources, As mentioned above. But, such solution still relates to a large amount of process of biomass resource and purifying to obtain raw material, and these treatment steps itself relate to a large amount of use of fossil oil.

In addition, the multiple raw material of �� processing requirement in a place, this can cause availability problem. If the route of any biological chemistry is avoided multiple raw material or reduced the quantity of raw material, so therefore it will be favourable.

Therefore, for acrylate monomer such as AA, MMA and MAA improvement, selectable, be still required based on the route of non-fossil fuel.

PCT/GB2010/052176 discloses the technique of the aqueous solution for manufacturing acrylate and methacrylic ester respectively from the solution of oxysuccinic acid and citromalic acid and their salt.

The people Ind.Eng.Chem.Res.1994,33,1989-1996 such as Carlsson have disclosed the high temperature at 360 DEG C and have had the methylene-succinic acid decarboxylation to MAA of the maximum yield of 70%, and wherein the acid of a part exists as alkali salt such as sodium itaconate. Unfortunate ground, the unexposed any purification process for reclaiming MAA from reaction medium of Carlsson. Carlsson discloses concentration relative to the freely acid increase of activity along with sodium salt of decomposition reaction. Selectivity is decline when the concentration of methylene-succinic acid raises before decomposition in the solution.

US4142058 discloses the extraction of the aqueous solution from acidity under counter-current flow of the use MMA of methacrylic acid and the mixture of toluene. Aqueous phase becomes refuse. US3968153 discloses the use butanone of vinylformic acid and/or methacrylic acid and extracting from aqueous phase of dimethylbenzene. US4956493 discloses and methacrylic acid is used from its aqueous solution the saturated chain fatty race hydrocarbon with 6 to 9 carbon atoms as solvent extraction. Dimethylbenzene and toluene it is said problem. EP710643 uses organic solvent from its aqueous solution extraction methacrylic acid and uses water treatment organic extract with the auxiliary close sour citraconic acid of boiling point and the removing from extract of toxilic acid. US4879412 with JP193740/1989 is discussed by the process of the use deacidite of organic phase and US5196578 discloses the similar technique using amine. Technique has problem, because they introduce other impurity and can cause the by product of the polymerization causing equipment failure of methacrylic acid.

Those skilled in the art will recognize the condition of the solution that the instruction according to people such as Carlsson produces and will be not suitable for follow-up solvent extraction, because the high density of the lower concentration of MAA and alkali. The basic salt of AA and MAA has the high-dissolvability in water and very low solubleness in organic solvent.

Unexpectedly, it has now been discovered that, AA and MAA can use the receipts rate unexpectedly improved to be extracted from water-based decarboxylic reaction medium under the existence of basic catalyst. In addition, extraction process allows basic solution to be recovered into after extraction in decarboxylic reaction, make for single the adding of alkali being used to be implemented from continuous print decarboxylation and the extraction process of dicarboxylic acid and tricarboxylic acid generation AA and MAA so that the reaction of base catalysis can be performed continuously.

According to the first aspect of the invention, there is provided and extract (methyl) acrylic acid from aqueous reaction medium, described aqueous reaction medium is by least one alkaline catalysts in aqueous and is selected from toxilic acid, fumaric acid, oxysuccinic acid, methylene-succinic acid, citraconic acid, the at least one dicarboxylic acid of methylfumaric acid and citromalic acid or its mixture is formed and decarboxylate containing its base catalysis comprising (methyl) vinylformic acid and/or (methyl) propylene acid-alkali salt, described method comprises and organic solvent is introduced into described aqueous reaction medium so that by described (methyl) vinylformic acid solvent extraction to the step in organic phase, wherein said method is characterised in that dicarboxylic acid and/or its presoma described at least one of additional quantity are added in described aqueous reaction medium to strengthen described (methyl) vinylformic acid solvent extraction in described organic solvent.

Preferably, described aqueous phase extract in (methyl) acrylic acid concentration be at least 0.05moldm^-3, it is more preferable to ground is 0.1moldm at least^-3, it is most preferred that ground is 0.2moldm at least^-3, especially at least 0.3 or 0.4moldm^-3. In rhythmic reaction, the starting point that this concentration is applicable to the reaction medium in the beginning extracted and is applicable in extracting in a continuous process. (methyl) acrylic acid concentration in the end of extraction will depend on the quantity in stage, but will be preferably lower than the 50% of beginning level, it is more preferable to ground 30%, it is most preferred that ground 20%.

Advantageously, cause to the better extraction in organic phase with (methyl) acrylic acid concentration of these levels.

Usually, alkaline catalysts volumetric molar concentration in aqueous reaction medium (methyl) acrylic acid from during its extraction being��overall acid concentration mol/mol wherein, more preferably, alkaline catalysts volumetric molar concentration during extracting��75%mol/mol of overall acid concentration, most preferably, alkaline catalysts volumetric molar concentration in aqueous reaction medium is acrylic acid at (methyl) is��non-(methyl) acryllic acid concentration mol/mol during its extraction, more particularly, during extracting��non-(methyl) acryllic acid concentration mol/mol 80%.

Preferably, alkaline catalysts is maintained at during described extraction process than the mol level of described at least one dicarboxylic acid and/or its presoma and is determined accordingly relative to the amount of the dicarboxylic acid forming the level of sub-stoichiometry of its first acid salt and be added into.

Mixture for the suitable dicarboxylic acid producing methacrylic acid is methylene-succinic acid, citromalic acid, citraconic acid and methylfumaric acid, it is more preferable to ground, methylene-succinic acid, citromalic acid and citraconic acid. Mixture for the acrylic acid suitable dicarboxylic acid of production is toxilic acid, fumaric acid and oxysuccinic acid, it is more preferable to ground, oxysuccinic acid.

Advantageously, extraction is without any need for the adding to aqueous phase of the outside agent of technique so that aqueous phase can easily and high-level efficiency be recovered in decarboxylic reaction medium for the further decarboxylation when base catalysis and further extraction subsequently. By this way, do not have completely or almost do not have other alkali to be required other dicarboxylic acid is treated to (methyl) vinylformic acid. Equally, the acid being only added in system is those acid that those dicarboxylic acid related in (methyl) acrylic acid production and/or presoma are sour or are formed in process of production. Outside mineral acid is not had to be required.

According to the second aspect of the invention, there is provided and extract (methyl) acrylic acid from aqueous reaction medium, described aqueous reaction medium is by least one alkaline catalysts in aqueous and is selected from fumaric acid, toxilic acid, oxysuccinic acid, methylene-succinic acid, citraconic acid, the at least one dicarboxylic acid of methylfumaric acid or citromalic acid or its mixture is formed and decarboxylate containing its base catalysis comprising (methyl) vinylformic acid or (methyl) propylene acid-alkali salt, described method comprises and organic solvent is introduced into aqueous reaction medium so that by described (methyl) vinylformic acid solvent extraction to the step in described organic phase, it is characterized in that alkaline catalysts is maintained at the level relative to the sub-stoichiometry forming its first acid salt than the level of described at least one dicarboxylic acid and/or its presoma during described extraction process.

Other aspect according to the present invention, the method that (methyl) vinylformic acid is extracted into the organic phase being in contact with it from aqueous reaction medium is provided, described aqueous reaction medium is by least one alkaline catalysts in aqueous and is selected from fumaric acid, toxilic acid, oxysuccinic acid, methylene-succinic acid, citraconic acid, the at least one dicarboxylic acid of methylfumaric acid or citromalic acid or its mixture is formed and decarboxylate containing its base catalysis comprising (methyl) vinylformic acid or (methyl) propylene acid-alkali salt, and described organic phase comprises the organic solvent suitable for described (methyl) vinylformic acid, it is characterized in that alkaline catalysts is maintained at the level relative to the sub-stoichiometry forming its first acid salt than the level relatively of described at least one dicarboxylic acid and/or its presoma in the period at least partially of described extraction in described aqueous reaction medium.

Aspect other again according to the present invention, there is provided and extract (methyl) acrylic acid from aqueous reaction medium, described aqueous reaction medium is by least one alkaline catalysts in aqueous and is selected from toxilic acid, fumaric acid, oxysuccinic acid, methylene-succinic acid, citraconic acid, the at least one dicarboxylic acid of methylfumaric acid or citromalic acid or its mixture is formed and decarboxylate containing its base catalysis comprising (methyl) vinylformic acid and/or (methyl) propylene acid-alkali salt, described method comprises described (methyl) vinylformic acid solvent extraction to the step in the organic phase comprising the organic solvent contacted with described aqueous reaction medium, wherein said method is characterised in that dicarboxylic acid described at least one of additional quantity and/or is added in the described aqueous reaction medium of the decarboxylate containing its base catalysis described in its presoma to strengthen described (methyl) vinylformic acid solvent extraction in described organic phase.

Preferably, the method for any aspect herein comprise after extraction from the follow-up process of organic phase described in described aqueous phase separation and described organic phase subsequently with from described organic solvent segregation (methyl) acrylic acid step described in extraction described extraction process. A suitable process of organic phase is that distillation is to obtain (methyl) vinylformic acid.

It will be appreciated that, it is that the dicarboxylic acid of diprotic acid can form its first and second acid salt with alkali, and term first acid salt should be understood accordingly and be not intended to refer to the salt of generation and the 2nd on dicarboxylic acid or its presoma or further acid groups but the first acid salt of only being formed.

Advantageously, by alkali is remained on the sub-stoichiometry first acid salt level relative to the dicarboxylic acid in aqueous medium/reaction medium and/or the level of presoma, (methyl) is acrylic acid to be modified to the extraction in suitable organic solvent.

Preferably, when the decomposition of the acid of the formation for MAA, organic solvent is the outside organic solvent relative to aqueous medium/reaction medium.

Preferably, at least some citraconic acid exists in an aqueous medium. Advantageously, this improves extraction. But, the most suitable acid is methylene-succinic acid at present, due to its commercial applicability, or citromalic acid.

Suitable presoma is one or more the presoma that can be recovered to produce in described dicarboxylic acid. Typically, presoma decomposes to produce described dicarboxylic acid by when temperature and pressure suitable. Accordingly, presoma can be regarded as the source of dicarboxylic acid. It will be appreciated that alkaline catalysts exists so that presoma decompose can advantageously such suitable when be alkali catalyzed. A kind of presoma suitable for methylene-succinic acid, citraconic acid, methylfumaric acid or citromalic acid is citric acid, citric acid can dehydrated and decarboxylation with at least one produced in methylene-succinic acid, citraconic acid, methylfumaric acid or by decarboxylation to produce citromalic acid. This reaction when temperature and pressure suitable and selectively occur under the existence of alkaline catalysts and must be not other the catalyzer being separated. But, have been found that, before extraction citric acid is added in aqueous medium/reaction medium also as the extraction of the auxiliary methacrylic acid of the acid being added into, also do not introduce the outside agent self needing to be removed from aqueous medium/reaction medium, because then citric acid can subsequently be processed to generate more dicarboxylic acid in continuous print process and from its methacrylic acid simultaneously.

According to the third aspect of the invention we, it is provided for produce (methyl) acrylic acid technique, comprise the following steps :-

Form at least one alkaline catalysts and it is selected from the aqueous medium of at least one dicarboxylic acid of fumaric acid, toxilic acid, oxysuccinic acid, methylene-succinic acid, citraconic acid, methylfumaric acid or citromalic acid or its mixture;

Under the existence of described at least one alkaline catalysts, make described at least one dicarboxylic acid decarboxylation with (methyl) vinylformic acid of producing in described aqueous medium and/or its alkali salt under appropriate conditions of temperature and pressure;

Organic solvent is introduced into described aqueous medium so that by described (methyl) vinylformic acid solvent extraction in organic phase;

It is characterized in that alkaline catalysts is maintained at the level relative to the sub-stoichiometry forming its first acid salt than the level of described at least one dicarboxylic acid and/or its presoma during described extraction process.

In herein any, described organic solvent can be introduced into described aqueous medium before or after decarboxylation.

Preferably, described sub-stoichiometry level exists, and if necessary, is kept during that part being implemented after being implemented by the acid being added into after reaction after at least described decarboxylation step of described extraction process herein.

According to the fourth aspect of the invention, it is provided for produce (methyl) acrylic acid technique, comprise the following steps :-

It is characterized in that dicarboxylic acid described at least one additional quantity and/or its presoma add in described aqueous medium, it is preferable that after described decarboxylation step, to strengthen described (methyl) vinylformic acid solvent extraction to the step in described organic phase.

Advantageously, according to certain embodiments of the present invention, also it is likely alkaline catalysts is remained on the level relative to the sub-stoichiometry forming its first acid salt than the level of described at least one dicarboxylic acid and/or its presoma during described decarboxylation.

Suitable organic solvent is extracted for (methyl) vinylformic acid and comprises hydrocarbon solvent or oxo solvent (oxygenatedsolvent), particularly C₄-C₂₀Hydrocarbon solvent. Hydrocarbon solvent can be aliphatic, aromatic or partially aromatic, saturated or unsaturated, ring-type, non-annularity or part ring-type, linear or side chain. Oxo solvent can be ester, ether or ketone. Suitable solvent comprises toluene, benzene, ethylbenzene, dimethylbenzene, Three methyl Benzene, octane, heptane, hexane, pentane, pentamethylene, hexanaphthene, suberane, cyclooctane, tetrahydrobenzene, methylcyclohexane, methylethylketone, methyl methacrylate or its mixture. Can also be used with the immiscible ionic liquid of water.

A preferred mixture for the solvent of the extraction of MAA is C₄-C₂₀Hydrocarbon solvent and MMA. A suitable mixture contains 1-40%MMA, and more typically 5-30%MMA, wherein surplus is made up of hydrocarbon solvent. In order to the preferred hydrocarbon solvent of object herein is toluene and dimethylbenzene.

It is preferred, however, that use only C₄-C₂₀Hydrocarbon, individually or with in the mixture of other hydrocarbon, as extractibility solvent. Preferably, relative (static) specific inductivity of each in hydrocarbon or the hydrocarbon in the mixture of hydrocarbon is less than 20 at 20 DEG C and barometric point, it is more preferable to ground is less than 8, it is most preferred that ground is less than 3. Accordingly, it is preferred for having at the hydrocarbon of 20 DEG C with relative (static state) specific inductivity in the scope of 1.6 to 20 of barometric point, it is more preferable to ground is in the scope of 1.7 to 8, it is most preferred that ground is in the scope of 1.8 to 3.

Preferably for the solvent of extraction of AA, there is with mixture being less than 20, be more preferably less than 10, be most preferably less than relative (static state) specific inductivity of 7 at 20 DEG C and barometric point. Typically, relative (static) specific inductivity is at least 1.6, more typically at least 2.0, the most at least 2.3. Accordingly, the solvent with relative (static) specific inductivity in the scope of 1.6 to 20 is preferred, it is more preferable to ground is in the scope of 2.0 to 10, it is most preferred that ground in the scope of 2.2 to 8, all at 20 DEG C and barometric point.

Dicarboxylic acid reactant and alkaline catalysts do not need ground to be the compound only existed in aqueous medium/reaction medium. The thermal decarboxylation that the compound of dicarboxylic acid and any other existence is dissolved in the aqueous solution for base catalysis jointly usually.

Preferably, the decarboxylation of the base catalysis of at least one dicarboxylic acid, being less than 350 DEG C of generations, is typically less than 330 DEG C, it is more preferable to ground is at height to 310 DEG C, it is most preferred that ground is at height to 300 DEG C. Under any circumstance, the preferred lower temperature of decarboxylation procedure for the present invention is 200 DEG C. The preferred temperature range of decarboxylation procedure for the present invention is between 200 to height is to 349 DEG C, it is more preferable to ground is between 220 to 320 DEG C, it is most preferred that ground between 240 to 310 DEG C, especially between 240 to 290 DEG C. One especially preferred temperature range be 240-275 DEG C, 245-275 DEG C the most especially.

The decarboxylic reaction of base catalysis occurs in its temperature in the liquid phase at aqueous medium/reaction medium. Typically, aqueous medium/reaction medium is the aqueous solution.

Preferably, the decarboxylation of base catalysis dicarboxylic acid reactant and preferably alkaline catalysts in aqueous time occur.

Advantageously, what carry out that decarboxylation prevents very big amount in lower temperature can be difficult to remove and can cause the production of the by product of other purification in industrial processes and process problem. Therefore, the selectivity unexpectedly improved that technique is provided in this temperature range. In addition, the decarboxylation of lower temperature uses the energy fewer than high-temperature decarboxylation and thus creates less carbon footprint.

Preferably, (methyl) acrylic acid extraction step is being less than or is equaling the decarboxylation temperature generation of above-detailed, but is more preferably being less than 100 DEG C, it is most preferred that ground is being less than 80 DEG C, is especially less than 60 DEG C. Under any circumstance, the preferred lower temperature of extraction step for the present invention is-10 DEG C, it is more preferable to 0 DEG C, ground. The preferred temperature range of extraction step for the present invention is between-10 to height to 349 DEG C, it is more preferable to ground is between-10 to 100 DEG C, it is most preferred that ground between 0 to 80 DEG C, especially between 10 to 60 DEG C, more particularly 30-50 DEG C.

Extraction step occurs in its temperature in the liquid phase at organic phase and aqueous phase.

Accordingly, extraction step occurs at its pressure in the liquid phase at organic phase and aqueous phase, and extraction occurs at barometric point usually.

Dicarboxylic acid can obtain from non-fossil fuel source. Such as, methylene-succinic acid, citromalic acid, citraconic acid or methylfumaric acid can from forerunner's style as citric acid or isocitric acid be produced by decarboxylation in suitable high temperature by dehydration and decarboxylation or from equisetic acid in suitable high temperature. It will be appreciated that alkaline catalysts exists so that presoma can stand dehydration and/or the decomposition of base catalysis. Citric acid and isocitric acid can itself produce by known zymotechnique and equisetic acid can by the former acid production. Accordingly, the technique of the present invention provides biological or substantially biological route directly to generate (methyl) acrylate with some form, and minimumization is to the dependence of fossil oil simultaneously.

US5849301 discloses for the technique from glucose production oxysuccinic acid and fumaric acid. US5766439 discloses the technique for the production of toxilic acid. The extraction that oxysuccinic acid is also the product such as Sucus Mali pumilae by producing in agricultural is available.

In order to keeping in the liquid phase under the temperature condition of reactant above, the decarboxylic reaction of at least one dicarboxylic acid is carried out at the suitable pressure exceeding barometric point. Suitable pressure in the liquid phase is kept to be greater than 200psi by the temperature range of reactant above, more suitably be greater than 300psi, be greater than 450psi the most suitablely and under any circumstance than reactant medium lower than it by the high pressure of pressure of boiling. The upper limit without pressure, but technician will operate in physical constraints and in equipment work difference, such as, be less than 10,000psi, be more typically less than 5,000psi, be the most typically less than 4000psi.

Preferably, above decarboxylic reaction is at about pressure between 200 to 10000psi. More preferably, react at about pressure between 300 to 5000psi, and more preferably about between 450 to 3000psi.

In a preferred embodiment, above reaction at aqueous medium/reaction medium at its pressure in the liquid phase.

Above reaction at aqueous medium/reaction medium at its temperature in the liquid phase and pressure.

As mentioned above, catalyzer is alkaline catalysts.

Preferably, catalyzer comprises OH^-The source of ion. Preferably, alkaline catalysts comprises metal oxide, oxyhydroxide, carbonate, acetate (acetate), alkoxide, supercarbonate or the dicarboxylic acid of decomposable asymmetric choice net or the salt of tricarboxylic acid, or more in the quaternary ammonium compound of; More preferably I race or II family metal oxide, oxyhydroxide, carbonate, acetate, alkoxide, supercarbonate or dicarboxylic acid or tricarboxylic acid or (methyl) acrylic acid salt. Alkaline catalysts can also comprise one or more amine.

Preferably, alkaline catalysts be selected from following in one or more: LiOH, NaOH, KOH, Mg (OH)₂��Ca(OH)₂��Ba(OH)₂��CsOH��Sr(OH)₂��RbOH��NH₄OH��Li₂CO₃��Na₂CO₃��K₂CO₃��Rb₂CO₃��Cs₂CO₃��MgCO₃��CaCO₃��SrCO₃��BaCO₃��(NH₄)₂CO₃��LiHCO₃��NaHCO₃��KHCO₃��RbHCO₃��CsHCO₃��Mg(HCO₃)₂��Ca(HCO₃)₂��Sr(HCO₃)₂��Ba(HCO₃)₂��NH₄HCO₃��Li₂O��Na₂O��K₂O��Rb₂O��Cs₂O��MgO��CaO��SrO��BaO��Li(OR¹)��Na(OR¹)��K(OR¹)��Rb(OR¹)��Cs(OR¹)��Mg(OR¹)₂��Ca(OR¹)₂��Sr(OR¹)₂��Ba(OR¹)₂��NH₄(OR¹), wherein R¹It is any C₁To C₆Side chain, non-branched or the alkyl group of ring-type, it is selectively replaced by one or more functional group; NH₄(RCO₂)��Li(RCO₂)��Na(RCO₂)��K(RCO₂)��Rb(RCO₂)��Cs(RCO₂)��Mg(RCO₂)₂��Ca(RCO₂)₂��Sr(RCO₂)₂Or Ba (RCO₂)₂, wherein RCO₂It is selected from malate, fumaric acid esters, maleic acid ester, citromalic acid ester, methylfumaric acid ester, citraconate, itaconic ester, citrate, barkite and (methyl) acrylate; (NH₄)₂(CO₂RCO₂)��Li₂(CO₂RCO₂)��Na₂(CO₂RCO₂)��K₂(CO₂RCO₂)��Rb₂(CO₂RCO₂)��Cs₂(CO₂RCO₂)��Mg(CO₂RCO₂)��Ca(CO₂RCO₂)��Sr(CO₂RCO₂)��Ba(CO₂RCO₂)��(NH₄)₂(CO₂RCO₂), wherein CO₂RCO₂It is selected from malate, fumaric acid esters, maleic acid ester, citromalic acid ester, methylfumaric acid ester, citraconate, itaconic ester and barkite; (NH₄)₃(CO₂R(CO₂)CO₂)��Li₃(CO₂R(CO₂)CO₂)��Na₃(CO₂R(CO₂)CO₂)��K₃(CO₂R(CO₂)CO₂)��Rb₃(CO₂R(CO₂)CO₂)��Cs₃(CO₂R(CO₂)CO₂)��Mg₃(CO₂R(CO₂)CO₂)₂��Ca₃(CO₂R(CO₂)CO₂)₂��Sr₃(CO₂R(CO₂)CO₂)₂��Ba₃(CO₂R(CO₂)CO₂)₂��(NH₄)₃(CO₂R(CO₂)CO₂), wherein CO₂R(CO₂)CO₂It is selected from citrate, isocitric acid ester and rhizome of Chinese monkshood acid esters; First amine, ethamine, propylamine, butylamine, amylamine, own amine, hexahydroaniline, aniline; And R₄NOH, wherein R is selected from methyl, ethyl propyl, butyl. More preferably, alkali be selected from following in one or more: LiOH, NaOH, KOH, Mg (OH)₂��Ca(OH)₂��Ba(OH)₂��CsOH��Sr(OH)₂��RbOH��NH₄OH��Li₂CO₃��Na₂CO₃��K₂CO₃��Rb₂CO₃��Cs₂CO₃��MgCO₃��CaCO₃��(NH₄)₂CO₃��LiHCO₃��NaHCO₃��KHCO₃��RbHCO₃��CsHCO₃��Mg(HCO₃)₂��Ca(HCO₃)₂��Sr(HCO₃)₂��Ba(HCO₃)₂��NH₄HCO₃��Li₂O��Na₂O��K₂O��Rb₂O��Cs₂O; NH₄(RCO₂)��Li(RCO₂)��Na(RCO₂)��K(RCO₂)��Rb(RCO₂)��Cs(RCO₂)��Mg(RCO₂)₂��Ca(RCO₂)₂��Sr(RCO₂)₂Or Ba (RCO₂)₂, wherein RCO₂It is selected from malate, fumaric acid esters, maleic acid ester, itaconic ester, citrate, barkite, (methyl) acrylate; (NH₄)₂(CO₂RCO₂)��Li₂(CO₂RCO₂)��Na₂(CO₂RCO₂)��K₂(CO₂RCO₂)��Rb₂(CO₂RCO₂)��Cs₂(CO₂RCO₂)��Mg(CO₂RCO₂)��Ca(CO₂RCO₂)��Sr(CO₂RCO₂)��Ba(CO₂RCO₂)��(NH₄)₂(CO₂RCO₂), wherein CO₂RCO₂It is selected from malate, fumaric acid esters, maleic acid ester, citromalic acid ester, methylfumaric acid ester, citraconate, itaconic ester, barkite; (NH₄)₃(CO₂R(CO₂)CO₂)��Li₃(CO₂R(CO₂)CO₂)��Na₃(CO₂R(CO₂)CO₂)��K₃(CO₂R(CO₂)CO₂)��Rb₃(CO₂R(CO₂)CO₂)��Cs₃(CO₂R(CO₂)CO₂)��Mg₃(CO₂R(CO₂)CO₂)₂��Ca₃(CO₂R(CO₂)CO₂)₂��Sr₃(CO₂R(CO₂)CO₂)₂��Ba₃(CO₂R(CO₂)CO₂)₂��(NH₄)₃₍CO₂R(CO₂)CO₂), wherein CO₂R(CO₂)CO₂It is selected from citrate, isocitric acid ester; Tetramethylammonium hydroxide and tetraethyl ammonium hydroxide. Most preferably, alkali be selected from following in one or more: NaOH, KOH, Ca (OH)₂��CsOH��RbOH��NH₄OH��Na₂CO₃��K₂CO₃��Rb₂CO₃��Cs₂CO₃��MgCO₃��CaCO₃��(NH₄)₂CO₃��NH₄(RCO₂)��Na(RCO₂)��K(RCO₂)��Rb(RCO₂)��Cs(RCO₂)��Mg(RCO₂)₂��Ca(RCO₂)₂��Sr(RCO₂)₂Or Ba (RCO₂)₂, wherein RCO₂It is selected from malate, fumaric acid esters, maleic acid ester, itaconic ester, citrate, barkite, (methyl) acrylate; (NH₄)₂(CO₂RCO₂)��Na₂(CO₂RCO₂)��K₂(CO₂RCO₂)��Rb₂(CO₂RCO₂)��Cs₂(CO₂RCO₂)��Mg(CO₂RCO₂)��Ca(CO₂RCO₂)��(NH₄)₂(CO₂RCO₂), wherein CO₂RCO₂It is selected from malate, fumaric acid esters, maleic acid ester, citromalic acid ester, methylfumaric acid ester, citraconate, itaconic ester, barkite; (NH₄)₃(CO₂R(CO₂)CO₂)��Na₃(CO₂R(CO₂)CO₂)��K₃(CO₂R(CO₂)CO₂)��Rb₃(CO₂R(CO₂)CO₂)��Cs₃(CO₂R(CO₂)CO₂)��Mg₃(CO₂R(CO₂)CO₂)₂��Ca₃(CO₂R(CO₂)CO₂)₂��(NH₄)₃₍CO₂R(CO₂)CO₂), wherein CO₂R(CO₂)CO₂It is selected from citrate, isocitric acid ester; And Tetramethylammonium hydroxide.

Catalyzer can be homogeneity or inhomogeneous. In one embodiment, catalyzer can be dissolved in liquid reactions mutually in. But, catalyzer can be suspended in reaction and can pass through mutually on the solid carrier on it. In this scenario, reaction is preferably maintained at liquid mutually, it is more preferable to ground aqueous phase, in.

Preferably, for the alkali OH of decarboxylic reaction^-: the effective mol ratio of acid is at 0.001-2:1, more preferably 0.01-1.2:1, most preferably 0.1-1:1, especially between 0.3-1:1. For alkali OH^-Effective mol ratio, it means to derive from the OH of the compound being concerned about^-The molar content of nominal.

For acid, its mean acid mole. Therefore, when monoatomic base, alkali OH^-: those mol ratios with the compound being concerned about are overlapped by the effective mol ratio of acid, but effectively not mol ratio with the compound being concerned about is overlapped by mol ratio when the alkali of binary or ternary.

Especially, this can be regarded as monoatomic base: the mol ratio of binary or tribasic carboxylic acid is preferably between 0.001-2:1, it is more preferable to ground 0.01-1.2:1, it is most preferred that ground 0.1-1:1, especially 0.3-1:1.

Because the deprotonation for the formation of the acid of salt only refers to the first acid deprotonation in the present invention, so when binary or ternary alkali, the mol ratio of above alkali will change accordingly.

Selectively, (methyl) acrylic acid product can be esterified to produce its ester. Potential ester can be selected from C₁-C₁₂Alkyl or C2-C₁₂Hydroxyalkyl, glycidyl, isobornyl, dimethyl aminoethyl, tripropylene glycol ester. Most preferably, ethanol or alkene for the formation of ester can derive from biogenic, such as biological methanol, bio-ethanol, biological butanol.

As mentioned above, presoma such as citric acid, isocitric acid or equisetic acid preferably when temperature and pressure suitable and the one being selectively decomposed in the dicarboxylic acid of the present invention under the existence of alkaline catalysts. Decomposing suitable condition for this kind is be less than 350 DEG C, is typically less than 330 DEG C, it is more preferable to ground is at height to 310 DEG C, it is most preferred that ground is at height to 300 DEG C. Under any circumstance, it it is 180 DEG C for the preferred lower temperature of decomposition. Decomposing preferred temperature range for presoma is between 190 to height is to 349 DEG C, it is more preferable to ground is between 200 to 300 DEG C, it is most preferred that ground between 220 to 280 DEG C, especially between 220 to 260 DEG C.

Presoma decomposition reaction occurs in its temperature in the liquid phase at aqueous reaction medium.

In order to keep when the presoma decomposition temperature of reactant above in the liquid phase, decarboxylic reaction is carried out at the suitable pressure exceeding barometric point. Suitable pressure in the liquid phase is kept to be greater than 150psi by the temperature range of reactant above, more suitably be greater than 180psi, be greater than 230psi the most suitablely and under any circumstance than reactant medium lower than it by the high pressure of pressure of boiling. The upper limit without pressure, but technician will operate in physical constraints and in equipment work difference, such as, be less than 10,000psi, be more typically less than 5,000psi, be the most typically less than 4000psi.

Preferably, presoma decomposition reaction is at about pressure between 150 to 10000psi. More preferably, react at about pressure between 180 to 5000psi, and more preferably about between 230 to 3000psi.

In a preferred embodiment, presoma decomposition reaction at reaction medium at its pressure in the liquid phase.

Preferably, presoma decomposition reaction with aqueous reaction medium at its temperature in the liquid phase and pressure.

Other aspect according to the present invention, it is provided that preparation (methyl) vinylformic acid or the polymkeric substance of (methyl) acrylate or the method for multipolymer, comprise the following steps:

(i) according to the 3rd or fourth aspect preparation (methyl) vinylformic acid of the present invention;

(ii) (methyl) acrylic acid selectable esterification described in preparation in (i), to produce described (methyl) acrylate;

(iii) (methyl) vinylformic acid described in preparation and/or the polymerization at the (ii) described ester of middle preparation in (i), selectively uses one or more comonomers, to produce its polymkeric substance or multipolymer.

Preferably, above (methyl) acrylate (ii) is selected from C₁-C₁₂Alkyl or C2-C₁₂Hydroxyalkyl, glycidyl, isobornyl, dimethyl aminoethyl, tripropylene glycol ester, more preferably ��-dimethyl-aminoethylmethacrylate, n-BMA, Propenoic acid, 2-methyl, isobutyl ester, hydroxy methyl methacrylate, Rocryl 410 or methyl methacrylate, it is most preferred that ground methyl methacrylate, ethyl propenoate, butyl methacrylate or butyl acrylate.

Advantageously, such polymkeric substance will have the monomer residue thing in the source except fossil oil that derives from of considerable part (if not all).

Under any circumstance, it is preferable that comonomer comprise such as monoene key unsaturated carboxylic acid and dicarboxylic acid and their derivative, such as ester, acid amides and acid anhydride.

Preferred comonomer is vinylformic acid especially, methyl acrylate, ethyl propenoate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2-EHA, Hydroxyethyl acrylate, isobornyl acrylate, methacrylic acid, methyl methacrylate, ��-dimethyl-aminoethylmethacrylate, propyl methacrylate, n-BMA, Propenoic acid, 2-methyl, isobutyl ester, methacrylic tert-butyl acrylate, 2-Ethylhexyl Methacrylate, hydroxyethyl methylacrylate, lauryl methacrylate(LMA), glycidyl methacrylate, Rocryl 410, isobornyl methacrylate, dimethylaminoethyl methacrylate, diacrylate tripropylene glycol ester, vinylbenzene, AAAAAA vinyl toluene, vinyl-acetic ester, isocyanic ester comprises toluene-2,4-diisocyanate and p, p '-methylene radical two isocyanic acid diphenyl, vinyl cyanide, divinyl, described acid mono in (i) of divinyl and vinylbenzene (MBS) and ABS or (ii) in described ester monomer with one or more any given copolymerization in comonomer in stand be not be selected from above (i) or (ii) in methacrylic acid or methacrylic ester monomer comonomer above in any.

Certainly, also it is the mixture likely using different comonomers. Comonomer itself or can not use the process quilt preparation identical with from monomer (i) or (ii) above.

Other aspect according to the present invention, it is provided that prepare polyacrylic acid, polymethyl acrylic acid, polymethacrylate, polymethylmethacrylate (PMMA) and polymethylmethacrylahomopolymer homopolymer or the multipolymer that the method for polymkeric substance or multipolymer is formed by aspect above.

Aspect other again according to the present invention, it is provided for the technique of the production of methacrylic acid, comprising :-

The source of the presoma acid being selected from equisetic acid, citric acid and/or isocitric acid is provided;

To the source of described presoma acid by source described in it be exposed under the presence or absence of alkaline catalysts sufficiently high temperature carry out decarboxylation and, if necessary, dehydrating step, to provide methylene-succinic acid, methylfumaric acid, citraconic acid and/or citromalic acid; And be used in and methacrylic acid be provided and/or strengthen it be extracted in organic phase according to the methylene-succinic acid provided in any technique in other the aspect of the present invention, methylfumaric acid, citraconic acid and/or citromalic acid.

For the source of equisetic acid, citric acid and/or isocitric acid, it means its acid and salt, such as itself I or II race metal-salt, and comprises the solution of its presoma acid and salt, such as its aqueous solution.

Selectively, salt can before presoma acid decarboxylation step, period or afterwards by acidifying to discharge free acid.

Preferably, the dicarboxylic acid reactant of the present invention or its presoma are exposed to this reaction conditions and continue suitable period time to cause required reaction, typically continue period time of at least 30 seconds, more preferably at least about 100 seconds, also more preferably at least about 120 seconds and most preferably at least about 150 seconds.

Typically, dicarboxylic acid reactant or its presoma are exposed to this reaction conditions and continue to be less than about 2000 seconds, are more typically less than about 1500 seconds, are also more typically less than period time of about 1000 seconds.

Preferably, the dicarboxylic acid reactant of the present invention or its presoma be exposed to this reaction conditions continue about 75 seconds to 2500 seconds between, more preferably about 90 seconds to 1800 seconds between and most preferably about 120 seconds to 800 seconds between period time.

Preferably, the dicarboxylic acid reactant of the present invention or its presoma are dissolved in water reaction is occurred under aqueous conditions.

The mode being defined from reaction above will be clear that, if presoma by decarboxylation and, if necessary, dewatering in reaction medium, so reaction medium can cause any aspect according to the present invention to be selected from the decarboxylation of base catalysis of dicarboxylic acid of toxilic acid, fumaric acid, oxysuccinic acid, methylene-succinic acid, citraconic acid, methylfumaric acid, citromalic acid or its mixture from least one that its presoma is produced simultaneously. Accordingly, the decarboxylation of presoma and, if necessary, the decarboxylation of the base catalysis of dehydration and at least one dicarboxylic acid can occur in a kind of reaction medium, and namely two processes can occur as one kettle way. If it is preferred, however, that presoma by decarboxylation and, if necessary, dehydration and substantially there is no base catalysis so that the decarboxylation of presoma and, if necessary, dehydration and at least one dicarboxylic acid base catalysis decarboxylation separation step in occur.

Preferably, the concentration of the dicarboxylic acid reactant in decarboxylic reaction is at least 0.1M, it is preferable that in its water-based source; More preferably at least about 0.2M, it is preferable that in its water-based source; Most preferably at least about 0.3M, it is preferable that in its water-based source, especially at least about 0.5M. Usually, water-based source is the aqueous solution.

Preferably, the concentration of the dicarboxylic acid reactant in decarboxylic reaction is less than about 10M, it is more preferable to ground is less than 8M, it is preferable that in its water-based source; More preferably it is less than about 5M, it is preferable that in its water-based source; More preferably it is less than about 3M, it is preferable that in its water-based source.

Preferably, the concentration of the dicarboxylic acid reactant in decarboxylic reaction is in the scope of 0.05M-20, typically 0.05-10M, more preferably 0.1M-5M, most preferably 0.3M-3M.

Alkaline catalysts can in liquid medium solubilized, liquid medium can be water or alkaline catalysts can be heterogeneous. Alkaline catalysts can in aqueous medium/reaction medium solubilized, make to react and exceed the decarboxylation of reactant to (methyl) acrylic acid base catalysis and/or the sour temperature that will occur at it to the decarboxylation of the base catalysis of dicarboxylic acid of presoma by reactant is exposed to, such as those temperature given above, temperature caused. Catalyzer can be in aqueous. Accordingly, catalyzer can be homogeneous or heterogeneous, but homogeneous typically. Preferably, the concentration (comprising the decomposition of presoma acid medium) in aqueous medium/reaction medium of catalyzer is at least 0.1M or bigger, it is preferable that in its water-based source; More preferably at least about 0.2M, it is preferable that in its water-based source; More preferably at least about 0.3M.

Preferably, the concentration (comprising the decomposition of presoma acid medium) in aqueous medium/reaction medium of catalyzer is less than about 10M, more preferably it is less than about 5M, more preferably be less than about 2M and, under any circumstance, it is preferable that be less than or equal reaction temperature and pressure by the concentration of the solution that reaches capacity.

Preferably, aqueous medium/reaction medium or presoma acid decompose in the volumetric molar concentration of OH-in the scope of 0.05M-20M, more preferably 0.1-5M, most preferably 0.2M-2M.

Preferably, reaction conditions is slightly acidic. Preferably, reacting pH is between about 2 to 9, it is more preferable to ground is between about 3 to about 6.

In order to avoid query, for term methylene-succinic acid, it means following formula compound (i)

In order to avoid query, for term citraconic acid, it means following formula compound (ii)

In order to avoid query, for term methylfumaric acid, it means following formula compound (iii)

In order to avoid query, for term citromalic acid, it means following formula compound (iv)

As mentioned above, the technique of the present invention can be homogeneous or heterogeneous. In addition, technique can be technique in batches or continuously.

Advantageously, a by product in the production of MAA can be the hydroxy-iso-butyric acid (HIB) existed with balancing at condition and the product MAA of the decomposition for dicarboxylic acid. Accordingly, the part of the product from decomposition reaction of MAA or overall separation migrates to MAA balance from HIB, thus generates other MAA in the subsequent disposal of solution during extraction process or after MAA is separated. Selectively, solvent can exist during decomposition reaction so that at least one part of methacrylic acid is extracted in organic medium during decomposition reaction.

Advantageously, a by product in the production of AA can be the hydroxy-propionic acid (HPA) existed with balancing at condition and the product A A of the decomposition for dicarboxylic acid. Accordingly, the part of the product from decomposition reaction of AA or overall separation migrates to AA balance from HPA, thus generates other AA in the follow-up process of solution during extraction process or after the separation of AA. Selectively, solvent can exist during decomposition reaction so that acrylic acid at least one part is extracted in organic medium during decomposition reaction.

If the compound of formula herein can exist as more than one steric isomer, such as formula above compound (iv), so all steric isomers are all included within the scope of the invention. Especially, R+ or the S-form of citromalic acid and the mixture of its racemize are included in the scope of term citromalic acid.

The feature contained herein whole can by with any combination in aspect above, in any combination.

In order to the better understanding of the present invention, and in order to illustrate how embodiment of the present invention can be put into practice, now by by way of example with reference to following drawings and Examples, in the accompanying drawings :-

Fig. 1 shows the concentration dependent that MAA is extracted in toluene;

Fig. 2 shows the graphic representation of partition ratio relative to the MMA mark in toluene of multiple acid;

Fig. 3 shows the graphic representation of relative distribution coefficient relative to the MMA mark in toluene of multiple acid and MAA;

Fig. 4 shows and adds alkali and dicarboxylic acid to the impact of the transfer of MAA between aqueous phase and organic phase;

Fig. 5 shows the distribution of vinylformic acid between water and toluene;

Fig. 6 shows the schematic diagram of the suitable equipment of the decomposition of the base catalysis for dicarboxylic acid.

Solvent extraction

Use following experiment condition, unless otherwise directed :-

0.1M acid

1:1 volume: volume of water: solvent

Room temperature

1 minute churning time; The 5min settling time

Solvent is toluene, unless otherwise directed

Use the analysis of HPLC

Comparing embodiment 1

The solvent using program test above a series of is to check the degree moving methacrylic acid from Transfer in Aqueous Solution. Result illustrates in Table 1.

Table 1

Solvent	Average % shifts	(static state) specific inductivity relatively
			Xylol	45.3	2.3
Toluene	48.2	2.4
			Hexane	27.6	1.9
Benzene	50.1	2.3
			Pentane	28.3	1.8
Hexanaphthene	26.9	2.0
			MMA	84.3	6.3

Present embodiment illustrates the MAA existed in free acid form can be extracted in multi-solvents effectively. Aromatic hydrocarbons obtains the highest extraction efficiency.

Comparing embodiment 2

After the part being expected a carboxylic acid and the dicarboxylic acid found from the decomposition of binary or triprotic acid is decomposed, it is possible to the monoprotic acid existed in aqueous and diprotic acid are compared their solubleness in toluene.

The solubleness that the often kind of acid being initially in water 0.1M solution is tested respectively in isopyknic toluene. Result illustrates in table 2

Table 2

Acid	It is transferred to the mark/% 12 of toluene-->
		One yuan
MAA	54.4
		CT	40.11
HIB	4.21
		PY	0
Binary
		IC	0
MC	0.64

MAA methacrylic acid

CT ��-crotonic acid

HIB hydroxy-iso-butyric acid

PY pyruvic acid

IC methylene-succinic acid

MC methylfumaric acid

It is insoluble for present embodiment illustrates useful dicarboxylic acid and tricarboxylic acid in for the production of the technique of MAA in toluene, and toluene is a kind of solvent that can be used to extract MAA. In addition, the HIB formed with balancing with MAA is not extracted in toluene by the pyruvic acid extracted using very big ratio and formed as undesired by product yet.

Comparing embodiment 3

The MAA of a series of different concns in the aqueous solution is extracted in toluene (by volume relative to aqueous solution 1:1). Percentage ratio solubleness illustrates in table 3.

Table 3

	[MAA]/M in starting aqueous solution	% is extracted than the aqueous solution with 1:1 toluene
			Comparing embodiment 3a	0.00743	12.69%
Comparing embodiment 3b	0.0148	20.07%
			Comparing embodiment 3c	0.02878	26.76%
Comparing embodiment 3d	0.05829	37.09%
			Comparing embodiment 3e	0.1215	52.00%
Comparing embodiment 3f	0.2479	60.51%
			Comparing embodiment 3g	0.3	63.60%
Comparing embodiment 3h	0.4778	68.67%
			Comparing embodiment 3j	0.7559	73.72%
Comparing embodiment 3k	0.9576	76.71%

The mark being transferred increases along with the concentration of MAA. Data from table 3 are mapped according to equation:

[MAA]_Toluene=K[MAA]² _Water

And the value K in equation is estimated as 14.6. Result is mapped in FIG.

It is concentration dependent that the present embodiment illustrates that MAA is extracted in toluene. In order to effectively extract, the concentration higher than 0.1M is preferred.

Comparing embodiment 4

It is prepared in the aqueous solution of each dicarboxylic acid of example in comparing embodiment 2. The solvent mixture of isopyknic toluene and methyl methacrylate (MMA) is used to extract these. The extraction degree obtained illustrates in table 4.

Table 4

The present embodiment illustrates that MMA can be added in toluene to improve the extraction efficiency of MAA. But, dicarboxylic acid and HIB are discussed above by the MMA level of the optimum extracted with very big amount wherein.

In order to the solubleness compared in partition ratio in organic solvent, each sample is converted to partition ratio based on following equation: [MAA]_Solvent=K[MAA]² _Water

Data figure 2 illustrates

Only MAA, ��-crotonic acid and hydroxy-iso-butyric acid have arbitrary solvent mutually in very big solubleness. The solubleness of component is in every case along with the mark of MMA increases.

Relative distribution coefficient can also change along with composition. Fig. 3 compares the ratio of the partition ratio for MAA with the partition ratio for other each acid.

Therefore comparing embodiment illustrates that so selectivity is higher if pure toluene is used. But, the use of some MMA allows the MAA of greater concn to be extracted, and reduces selectivity simultaneously.

Comparing embodiment 5

After adding 0.05M sodium hydroxide, it is determined that the solution extraction of 0.1MMAA in aqueous is in isopyknic toluene. The amount of the MAA being transferred drops to 26% from 48%. Result is before table 5 shown in two row

Embodiment 1-3

The methylene-succinic acid being enough to obtain 0.1M solution is added in the aqueous solution containing MAA+ sodium hydroxide of comparing embodiment 5 and MAA transfer is significantly improved to 44.7% and is extracted in toluene. Data illustrate in table 5. Citraconic acid or methylfumaric acid is used to replace methylene-succinic acid to repeat experiment. Closely similar result is obtained.

Table 5

Embodiment 4-30 and comparing embodiment 6-9

Be added into the NaOH containing different levels 0.1MMAA the aqueous solution in the various dicarboxylic acid of 0.1M concentration and tricarboxylic acid extracted by isopyknic toluene.

When naoh concentration increases, the amount of the MAA extracted wherein a kind of carboxylic acid of being added into exist lower than the two/tricarboxylic acid being added into not in the presence of more slowly decline. The most obvious with citric acid and methylfumaric acid effect. Table 6 shows experimental data, and experimental data illustrates in the diagram.

Table 6

	[MAA]/M	[NaOH]/M	Acid	[acid]	% shifts
						Comparing embodiment 1	0.1	0	Nothing		48
Comparing embodiment 5	0.1	0.05	Nothing		26.04
						Comparing embodiment 6	0.1	0	Methylene-succinic acid	0.1	47.99
Embodiment 4	0.1	0.025	Methylene-succinic acid	0.1	44.59
						Embodiment 5	0.1	0.05	Methylene-succinic acid	0.1	41.53
Embodiment 6	0.1	0.075	Methylene-succinic acid	0.1	30.7
						Embodiment 7	0.1	0.1	Methylene-succinic acid	0.1	20.88
Embodiment 8	0.1	0.125	Methylene-succinic acid	0.1	17.68
						Embodiment 9	0.1	0.15	Methylene-succinic acid	0.1	3.84
Comparing embodiment 7	0.1	0	Citraconic acid	0.1	47.58
						Embodiment 10	0.1	0.025	Citraconic acid	0.1	47.71
Embodiment 11	0.1	0.05	Citraconic acid	0.1	48.06
						Embodiment 12	0.1	0.075	Citraconic acid	0.1	47.29
Embodiment 13	0.1	0.1	Citraconic acid	0.1	45.52
						Embodiment 14	0.1	0.125	Citraconic acid	0.1	35.05
Embodiment 15	0.1	0.15	Citraconic acid	0.1	24.21
						Embodiment 16	0.1	0.2	Citraconic acid	0.1	8.12
Comparing embodiment 8	0.1	0	Methylfumaric acid	0.1	47.36
						Embodiment 17	0.1	0.025	Methylfumaric acid	0.1	46.98
Embodiment 18	0.1	0.05	Methylfumaric acid	0.1	46.32
						Embodiment 19	0.1	0.075	Methylfumaric acid	0.1	45.66
Embodiment 20	0.1	0.1	Methylfumaric acid	0.1	44.05
						Embodiment 21	0.1	0.125	Methylfumaric acid	0.1	39.16 15 -->
Embodiment 22	0.1	0.15	Methylfumaric acid	0.1	35.15
						Embodiment 23	0.1	0.2	Methylfumaric acid	0.1	23
Comparing embodiment 9	0.1	0	Citric acid	0.1	47.82

Embodiment 24	0.1	0.025	Citric acid	0.1	48.27
						Embodiment 25	0.1	0.05	Citric acid	0.1	48.12
Embodiment 26	0.1	0.075	Citric acid	0.1	47.44
						Embodiment 27	0.1	0.1	Citric acid	0.1	46.18
Embodiment 28	0.1	0.125	Citric acid	0.1	41.83
						Embodiment 29	0.1	0.15	Citric acid	0.1	39.19
Embodiment 30	0.1	0.2	Citric acid	0.1	28.35

Embodiment 31-34

Table 7 illustrates the higher extraction degree using the ratio of higher organic phase and aqueous phase to cause 0.3MMAA solution.

Table 7

	Water: toluene v/v	% shifts
			Embodiment 31	1:1	64
Embodiment 32	1:2	72
			Embodiment 33	1:3	76
Embodiment 34	1:4	85

Embodiment 35-39

The use that table 8 further illustrates continuous extraction can increase MAA transfer further. Starting soln is the 0.3MMAA in water.

Table 8

	Water: toluene v/v	% shifts
				1:1 volume
Embodiment 31	1:1	63.6
				1:2 volume
Embodiment 32	1:2	72.0
			Embodiment 35	2��1:1	80.2
	1:3 volume
			Embodiment 33	1:3	75.9
Embodiment 36	1:2+1:1	84.9
			Embodiment 37	3��1:1	88.1
	1:4 volume
			Embodiment 34	1:4	84.9
Embodiment 38	2��1:2	88.0
			Embodiment 39	4��1:1	92.4

Embodiment 40

In other experiment, the decomposition of 0.01M citromalic acid is undertaken by use reactive flow, to test toluene extraction use during reaction; In this experiment, before entering the reactor, the stream of the dicarboxylic acid aqueous solution mixes with the stream of toluene with identical speed. Condition is as follows: 0.01M citromalic acid (CM) in water and 50mMNaOH, and 2000psi, in variable temperature, has the fixing residence time of 480 seconds. Initial stream is made up of CM and NaOH being dissolved in the water of 50:50 volume ratio and toluene. Use HPLC analyze two of detection mutually in the receipts rate of product displayed in Table 9. To the absolute MAA receipts rate of the analysis instruction 3.42% of organic phase, not there is other the product detected. The receipts rate of the MAA detected in aqueous phase is 34.61%, therefore after cooling to ambient temperatures, for partition ratio=28.5 between toluene and aqueous phase of MAA. Therefore solvent can be added in aqueous phase before decomposing period and after cooling.

Table 9

	In aqueous phase^InspectionMeasure	Toluene mutually in^InspectionMeasure
			Mass balance	54.83	0.00
Transformation efficiency	93.25	0.00
			PY	3.62	0.00
CC	4.53	0.00
			IC	0.76	0.00
HIB	3.85	0.00
			CM	0.00	0.00
MC	0.71	0.00
			MAA	34.61	3.42

Legend :-IC methylene-succinic acid

MC methylfumaric acid

CC citraconic acid

HIB hydroxy-iso-butyric acid

PY pyruvic acid

Embodiment 41-46 and comparing embodiment 10

The mixture preparing diprotic acid and methacrylic acid is containing the solution in the water of each acid of 0.1M. Sodium hydroxide is added in each solution with different concentration as shown in table 10. At room temperature use the toluene extraction water solution of same volume. Amount in organic layer and aqueous layer is shown in table.

Table 10

						Water	Toluene
									[NaOH]	[MAA]	[CC]	[IC]	[MC]	[MAA]	[MAA]
Comparing embodiment 10	0	0.1	0.1	0.1	0.1	0.052	0.048
								Embodiment 41	0.025	0.1	0.1	0.1	0.1	0.048	0.052
Embodiment 42	0.05	0.1	0.1	0.1	0.1	0.050	0.050
								Embodiment 43	0.075	0.1	0.1	0.1	0.1	0.052	0.048
Embodiment 44	0.1	0.1	0.1	0.1	0.1	0.051	0.049 17 -->
								Embodiment 45	0.125	0.1	0.1	0.1	0.1	0.050	0.050
Embodiment 46	0.15	0.1	0.1	0.1	0.1	0.051	0.049

Under the existence of the dicarboxylic acid of the combination of 0.3M, the concentration on the MAA extracted that adds of alkali does not have impact. In fact, by with the comparing and table 5 of the data in embodiment 5, however, be evident that the amount extracted is with not have dicarboxylic acid identical with the solution of alkali. This existence demonstrating dicarboxylic acid prevents the validity that organic solvent dissolution degree loses in the presence of a base.

Comparing embodiment 11

With comparing embodiment 3 in identical when use the toluene extraction solution of vinylformic acid in water, except acid is changed into AA from MAA.

Initial concentration and the amount being extracted in toluene are shown in table 11.

Table 11

	Concentration/M	[organic]/M	[water]/M)
				Comparing embodiment 11a	1	0.20	0.80
Comparing embodiment 11b	0.75	0.12	0.63
				Comparing embodiment 11c	0.5	0.064	0.44
Comparing embodiment 11d	0.25	0.026	0.22
				Comparing embodiment 11e	0.125	0.0070	0.12
Comparing embodiment 11f	0.0625	0.0025	0.060
				Comparing embodiment 11g	0.0312	0.00098	0.030
Comparing embodiment 11h	0.0156	0.00052	0.015
				Comparing embodiment 11j	0.0078	0.00021	0.0076

Relative concentration between aqueous phase and organic phase is by according to equation [AA_Toluene]=K[AA_Water]²Map and figure 5 illustrates.

Extremely good fitting of a straight line has much lower than embodiment 3 slope, shows AA more preference aqueous layer.

Comparing embodiment 12

In order to increase the solubleness of AA in organic layer, it may be necessary to higher polarity. Use the extraction of the research 0.1MAA aqueous solution of the mixture between isopyknic toluene and butanone.

	% is extracted	% is extracted
			% butanone	Toxilic acid	Vinylformic acid
0	0	5.01
			10	0.32	14.57
20	1.46	25.26
			30	3.41	35.45
40	5.19	44.14
			50	10.62	53.47
60	10.77	57.31
			70	15.01	63.39 18 -->
80	19.88	67.47
			90	27.09	70.04
100	34.32	65.56

When butanone concentration increases, there is very big increase in extraction degree, although the selectivity decline of extraction. Permission is enough effectively separated by the separation of significant improvement and to the suitable selection of the solvent of middle polarity by the mixture likely containing sodium salt by demonstrating between vinylformic acid solubleness and toxilic acid solubleness, and wherein vinylformic acid can be purified further by such as distilling.

The experiment that preparation embodiment-use flowing reactive carries out uses the program as hereafter summarized.

Flowing reactive program

Preparation comprises the methylene-succinic acid with the concentration of 0.5M, citraconic acid, methylfumaric acid or citromalic acid and also supplies solution with the reactant of the sodium hydroxide of the concentration of 0.5M. Methylene-succinic acid (>=99% used) obtain (catalogue numbering: L2,920-4) from SigmaAldrich; Citraconic acid (98+%) obtains (L044178) from AlfaAesar; Methylfumaric acid (99%) obtains (catalogue numbering: 13,104-0) from SigmaAldrich. Citromalic acid solution by solid (R)-(-)-citromalic acid (can be commercially available from VWRInternational) and sodium hydroxide catalyst be dissolved in nanometer pure water to required concentration to be produced.

Be used for acid/NaOH solvation deionized water first in ultrasonic bath (30KHz) by supersound process period of degassed 5 minutes.

This reactant is for entering solution by the Gilson305HPLC pump module by being equipped with Gilson10SC pump head for entering in reactor assembly. The speed that reactant supplies solution to be pumped in reactor assembly depends on required residence time and the volume of reactor. Supplying speed also to depend on the density of reaction medium, the density of medium reaction depends on again temperature of reaction.

For entering solution, by by 1/16, " internal diameter stainless steel (SS316) pipe (Sandvik) is pumped to reactor to reactant. Reactor is by 1/2, and " the straight joint section of SS316 pipe forms, and it is encapsulated in the aluminium block being equipped with two 800WWatlow cartridge heater. The transition from 1/16 " to 1/2 " of SS316 pipeline use SwagelokSS316 sloper be implemented and need 1/8 " middle ladder (namely 1/16 " pipe to 1/8 " pipe to 1/2 " of pipe is managed).

The volume of reactor is calculated in theory, and is identified difference in weight when reactor is filled by water and when it is dry; For described experiment, the volume of reactor is 19.4cm³. 1/2 " after pipe ' reactor ', pipeline is reduced to 1/16 ", then contact SwagelokSS3161/16 " crossbeam. At this crossbeam place, thermopair (K type) is used to monitor the temperature exporting Gong to enter.

Reactor volume (for residence time) be defined as pipe at the 1/2 " volume of joint section being disposed immediately between two 1/2 " to 1/8 " current regulators before and after aluminium block.

Product mixtures is finally passed through heat exchanger (in the length of 1/4 " 1/8 in pipe " pipe, cold water adverse current is by it) and manual Tescom back-pressure regulator, manually Tescom back-pressure regulator back pressure (pressure of the whole system being applied between this point and pump head) is produced: the pressure adopted is 3000psi for described all experiments. Sample was collected in the vial before being prepared for analyzing.

Being used, for the temperature required for reaction, thermostatted (800P) realization being equipped with Gefran controller, it regulates the power being applied in two Watlow cartridge heaters. The experiment of each group relates in the work of single temperature, and changes residence time between each operation. Flow required for running for first time is arranged at Gilson pump module. Pump then at the only pumping deionized water in period of about 20 minutes so that the heat trnasfer between aluminium block has become consistent. When by be positioned at reactor outlet for enter position thermopair instruction temperature when not changing (being accurate to 1 DEG C) period more than 5 minutes, heat trnasfer is regarded as reaching balance. In this stage, the entrance of pump is transferred to the container of the reaction-ure mixture prepared from the container of deionized water. Total volume (comprising reactor) of equipment is the about twice of the volume of its reactor. This is determined by experiment before. For specific flow, reaction-ure mixture maintenance pumping continues about three times that it has started the period required for occurring from final outlet, is reached to guarantee the stable state of reaction. The 20ml sample of collecting device outlet solution is for analysis after which time. Both the speed that the outlet collection rate of solution and reaction soln are consumed all by relative to time interocclusal record to monitor the consistence of pumping efficiency. After the specific sample collection run, pump intake is switched the container being back to deionized water, and flow is increased to the period that its maximum value continues about 10 minutes, to guarantee that all remaining material from operation before is all by from cleaned system. Then residence time to be studied subsequently is repeated this program.

Analyze

The quantitative analysis of product uses and is equipped with the Agilent1200 Series HPLC System of multi-wavelength UV detector to realize. Product is used the PhenomenexRezexRHM monose H being maintained at 75 DEG C that protected post protects⁺(8%) post separation. The method used is degree such as grade, implements water-based 0.005MH₂SO₄The 0.4ml/min flow of moving phase. The compound contained in product sample is found to have and can carry out 210nm(bandwidth 15nm) the UV absorbancy of optimum at minimal wave length place of MWD detector. The UV detection that all product compounds are calibrated them by their UV absorbancy is correlated with relative to the scope of concentration. Determine the linear response range of often kind of compound, and the most compatible scope of concentration found for all compounds interested is 5 �� 10^-3M to 1 �� 10^-3Between M. Therefore, 1 to 100 dilution that enough detection by quantitative of most of product are used in the sample obtained from equipment before HPLC analyzes realizes (when the dilution of 1 to 100 will mean when use 0.5M reaction soln, any with the product of the receipts rate generation between 20%-100% by the linear response range falling into concentration). If compound falls into this linear response range outside (being such as less than the receipts rate of 20%), so use the dilution of 1 to 10 to carry out the 2nd HPLC and analyze. Use 1 to 10 dilution process can not by accurately quantitative any sample be considered to be in concentration trace and therefore can ignore.

Program

Carry out following program. First preparation comprises the reagent mixture of acid and sodium hydroxide. Use density (calculating from the thermometer) calculating of reactor volume and water in order to the flow required for realizing residence time.

Fig. 6 shows the schematic diagram of the equipment for the present invention. Reaction soln 18 is arranged in the receptor 20 being connected to entrance 16. Entrance is connected to reactant pump 2 through conduit 22, and reactant pump 2 can operate solution 18 to be pumped to reactor tube 24, and this pipe is accommodated in along in the cartridge heater 26 of reactor 24 length circumference extension. Conduit 22 between pump 2 and reactor 24 is advanced past the valve 28 for operating control, pressure monitor 30 and relief valve 32 from pump. In addition, the switch 34 that trips is connected to pressure monitor 30, reactant pump 2 and monitoring temperature device 14. Monitoring temperature device 14 is arranged in conduit 22 closely after reactor 24 and before outlet (6). In addition, after monitor 14, conduit advances to outlet through strainer 36, heat exchanger 8 and back pressure regulator 4. Exporting 6 places, product is collected in be collected in receptor 38.

Reactor 24 also comprises temperature control unit 10,12 to control the temperature of reactor 24. Equipment also comprises quench system, and quench system comprises the independent entrance 40 for the quench water 44 in quench water receptor 42. Entrance 40 is connected to outlet 6 through conduit 46, and conduit 46 comprises independent quench pump 48, is the valve 50 of the control for quench water after quench pump 48. Quench water conduit 46 locates contact reacts conduit 22 with quenching any reaction after the reactor after the monitoring temperature device 14 being adjacent to reactor 24 and before strainer 36. Quench pump 48 and temperature regulator unit 10,12 are also connected to the tripping operation switch 34 for being shut down when tripping operation standard meets.

Reactor pump 2 is unlocked and deionized water is pumped in system. Back pressure regulator 4 is little by little adjusted to required pressure (3000psi).

The time that pump operated efficiency expends by recording the water from system outlet 6 collection 20ml volumes is by with 5mlmin^-1Check. > 90% efficiency is acceptable.

Then pumping capacity is set to run required pumping capacity.

The water supply (not shown) of heat exchanger 8 is set to be low to moderate medium flowing, depends on the temperature of reaction for testing and pumping capacity.

The well heater thermostatted 10 being equipped with temperature regulator 12 is set to run required temperature.

Once required temperature is reached (as indicated by thermostatted 10), reactor outlet temperature is monitored by temperature of reactor monitor 14, until value (being accurate to 1 DEG C) is observed keeps the static period (this expends about 20 minutes usually) continuing at least 5 minutes.

By being switched to from deionized water container (not shown), this requirement stopping pump of reagent mixture container 18(prepared flows several seconds pump intake 16). The original volume of the reagent mixture in container 18 is recorded.

Calculating can indicate and will start to export from system the period before 6 appearance at product solution. But, in practice, this is left the vision of the bubble of equipment (generating from the decomposition of reagent) and the sense of hearing exists confirmation. This period being allowed to continue to occur in order to product solution to expend �� period of 3. This guarantees that product mixtures is homogeneous.

Product solution at outlet 6,20ml is collected and time that this collection expends is recorded. The final time of reagent mixture and volume reading are also obtained.

After product collection, pump intake is transferred and is back to deionized water container, and pump is set to " main pattern " (maximum flow) and is left standstill the period of about 10 minutes.

Then the flow of pump is set in order to the value required for follow-up operation.

Again, reactor outlet temperature is monitored and on duty be considered as stable (this expends about 10 minutes usually) when the period of at least 5 minutes does not change.

This experimental technique is repeated, until being carried out to test required all operations. After all operations have been done, deionized water used the pump with main pattern be pumped in system and well heater (thermostatted) be cut off.

When reactor outlet temperature has dropped to lower than 80 DEG C, pump is cut off and the water supply of heat exchanger is also stopped.

Methacrylic acid extraction

Isopyknic toluene is used to extract the solution prepared according to preparation procedure above. The experiment of first group does not have extra acid be added into. In the second set, acid for initial pyrolytic decomposition is added into so that dicarboxylic acid (methylene-succinic acid, citraconic acid, methylfumaric acid, citromalic acid) adds that total concentration of 2-hydroxy-iso-butyric acid equals 0.5M, and this is the initial concentration for initial decomposition. The measurer for the extraction when there is the alkali of high density that adds that result in table 10 shows acid has very big impact.

Table 10

Comparing embodiment 12

Study the efficiency to extract to 2-butanone and o-Xylol than the MAA in the mixture of 75:25. The existence in this organic mixture of dimethylbenzene partly fetters the solubleness in aqueous phase of butanone, and this is the problem important when butanone is used as organic phase individually; This especially than, being reported as the distribution coefficient of MAA is about K=7.00²³Maximum value. In this case, it has been found that the MAA of about 80% is extracted in organic phase, this shows as extremely expects; But, other the dicarboxylic acid (i.e. methylene-succinic acid, citric acid etc.) related in decomposition experiment also demonstrates the avidity slightly to organic phase of height to 11%.

Note with the application jointly with this specification sheets simultaneously ground or filed before this specification sheets and read to the public common with this specification sheets all papers opened and document, and the content of all such papers and document is incorporated to herein by reference.

All features disclosed in this specification sheets (comprising any adjoint claim, summary and accompanying drawing), and/or all steps of disclosed any method or technique, can be combined with any combination, except in wherein such feature and/or step at least some is the combination mutually arranging him.

This specification sheets (comprise any adjoint claim, summary and accompanying drawing) disclosed in each feature can serviced replace in selectable feature that is identical, equivalence or similar purpose, unless separately there is statement clearly. Therefore, unless separately there is statement clearly, otherwise each disclosed feature be a general series equivalence or the only example of similar feature.

The invention is not restricted to the details of embodiment above. The present invention's expansion is to one of any novelty or the combination of any novelty of feature disclosed in this specification sheets (comprising any adjoint claim, summary and accompanying drawing), or expansion is to one of any novelty or the combination of any novelty of disclosed any method or the step of technique.

Claims

1. one kind extracts (methyl) acrylic acid from aqueous reaction medium, described aqueous reaction medium is by least one alkaline catalysts in aqueous and is selected from toxilic acid, fumaric acid, oxysuccinic acid, methylene-succinic acid, citraconic acid, the at least one dicarboxylic acid of methylfumaric acid and citromalic acid or its mixture is formed and decarboxylate containing its base catalysis comprising (methyl) vinylformic acid and/or (methyl) propylene acid-alkali salt, described method comprises and organic solvent is incorporated in described aqueous reaction medium so that by described (methyl) vinylformic acid solvent extraction to the step in organic phase, wherein said method is characterised in that dicarboxylic acid and/or its presoma described at least one of additional quantity are added in described aqueous reaction medium to strengthen described (methyl) vinylformic acid solvent extraction in described organic solvent.

2. method according to claim 1, wherein in aqueous phase extracts, (methyl) acrylic acid concentration is at least 0.05moldm^-3��

3. method according to claim 1, wherein alkaline catalysts is maintained at during described extraction process than the mol level of described at least one dicarboxylic acid and/or its presoma and is determined accordingly relative to the amount of the dicarboxylic acid forming the level of sub-stoichiometry of its first acid salt and add.

4. method according to claim 1, wherein said dicarboxylic acid and/or its presoma are selected from citric acid, methylene-succinic acid, citromalic acid, citraconic acid and methylfumaric acid or its mixture.

5. method according to claim 1, wherein said dicarboxylic acid is selected from toxilic acid, fumaric acid and oxysuccinic acid or its mixture.

6. one kind extracts (methyl) acrylic acid from aqueous reaction medium, described aqueous reaction medium is by least one alkaline catalysts in aqueous and is selected from fumaric acid, toxilic acid, oxysuccinic acid, methylene-succinic acid, citraconic acid, the at least one dicarboxylic acid of methylfumaric acid or citromalic acid or its mixture is formed and decarboxylate containing its base catalysis comprising (methyl) vinylformic acid or (methyl) propylene acid-alkali salt, described method comprises and organic solvent is incorporated in described aqueous reaction medium so that by described (methyl) vinylformic acid solvent extraction to the step in described organic phase, it is characterized in that alkaline catalysts is maintained at the level relative to the sub-stoichiometry forming its first acid salt than the level of described at least one dicarboxylic acid and/or its presoma during described extraction process.

7., according to method in any one of the preceding claims wherein, wherein when described (methyl) vinylformic acid is methacrylic acid, described organic solvent is the outside organic solvent relative to described reaction medium.

8., according to method in any one of the preceding claims wherein, wherein said dicarboxylic acid is selected from citromalic acid or methylene-succinic acid.

9., for the production of (methyl) acrylic acid technique, comprise the following steps :-

Organic solvent is incorporated in described aqueous medium so that by described (methyl) vinylformic acid solvent extraction in organic phase;

10., for the production of (methyl) acrylic acid technique, comprise the following steps :-

It is characterized in that dicarboxylic acid described at least one additional quantity and/or its presoma join in described aqueous medium to strengthen described (methyl) vinylformic acid solvent extraction to the step in described organic solvent.

11. methods according to any one of claim 1-10 or technique, wherein described organic solvent for the extraction of (methyl) vinylformic acid comprises hydrocarbon solvent or oxo solvent.

12. method according to claim 11 or techniques, wherein said solvent comprises toluene, benzene, ethylbenzene, dimethylbenzene, Three methyl Benzene, octane, heptane, hexane, pentane, pentamethylene, hexanaphthene, suberane, cyclooctane, tetrahydrobenzene, methylcyclohexane, methylethylketone, methyl methacrylate or its mixture; Or ionic liquid immiscible with water.

13. method according to claim 11 or techniques are wherein C for extracting the mixture of the solvent of MAA₄-C₂₀Hydrocarbon solvent and MMA.

Prepare the polymkeric substance of (methyl) vinylformic acid or (methyl) acrylate or the method for multipolymer, comprise the following steps for 14. 1 kinds:

I () prepares (methyl) vinylformic acid any one of claim 9-13;

(ii) described (methyl) vinylformic acid of esterification preparation in (i) optionally is to produce described (methyl) acrylate;

(iii) the described ester of described (methyl) vinylformic acid and/or preparation in (ii) that optionally are aggregated in preparation in (i) with one or more comonomers is to produce its polymkeric substance or multipolymer.

15. 1 kinds, for the production of the technique of methacrylic acid, comprising :-

To the source of described presoma acid by source described in it be exposed under the presence or absence of alkaline catalysts sufficiently high temperature carry out decarboxylation and, if necessary, dehydrating step, to provide the dicarboxylic acid being selected from methylene-succinic acid, methylfumaric acid, citraconic acid and/or citromalic acid; And

Be used in the technique according to any one of claim 1-13 produce described dicarboxylic acid.

16. 1 kinds of methods that (methyl) vinylformic acid is extracted into the organic phase being in contact with it from aqueous reaction medium, described aqueous reaction medium is by least one alkaline catalysts in aqueous and is selected from fumaric acid, toxilic acid, oxysuccinic acid, methylene-succinic acid, citraconic acid, the at least one dicarboxylic acid of methylfumaric acid or citromalic acid or its mixture is formed and decarboxylate containing its base catalysis comprising (methyl) vinylformic acid or (methyl) propylene acid-alkali salt, and described organic phase comprises the organic solvent suitable for described (methyl) vinylformic acid, it is characterized in that alkaline catalysts is maintained at the level relative to the sub-stoichiometry forming its first acid salt than the level relatively of described at least one dicarboxylic acid and/or its presoma in the period at least partially of described extraction in described aqueous reaction medium.

17. methods according to claim 1, wherein said organic solvent contacts with described aqueous reaction medium, and described aqueous reaction medium comprises the decarboxylate of described base catalysis.

18. methods according to claim 1, comprise after extraction from the follow-up process of organic phase described in described aqueous phase separation and described organic phase subsequently with from described organic solvent segregation (methyl) acrylic acid step described in extraction described extraction process.

19. methods according to claim 1, wherein said organic solvent was introduced into described aqueous medium before or after decarboxylation.

20. methods according to claim 1, wherein the level of the described sub-stoichiometry of alkali exists, and if necessary, is kept during that part being implemented after being implemented after reaction after at least described decarboxylation step of described extraction process.

21. methods according to claim 1, wherein the level of the described sub-stoichiometry of alkali is kept from start to finish in described reaction and described extraction.

22. methods according to any one of claim 1-3, wherein dicarboxylic acid and/or its presoma are selected from citric acid, methylene-succinic acid, citromalic acid and citraconic acid or its mixture.

23. methods according to any one of claim 1-3, wherein said dicarboxylic acid is oxysuccinic acid.

24. methods according to any one of claim 1-10 or technique, wherein described organic solvent for the extraction of (methyl) vinylformic acid is C₄-C₂₀Hydrocarbon solvent.